Wednesday, November 16, 2011

Belt Driving Impressions

I've wanted to try a bicycle with a belt drive for some time, but they are not exactly mainstream around these parts. So when I saw a belt drive Seven Cafe Racer in my size at the Ride Studio Cafe last week, I seized the opportunity and took it out for a ride. The belt drive Cafe Racer is a single speed version of this bike, one of Seven's commuter models. I will save my impressions of the bicycle itself for a different post, focusing for now on my impressions of this unique drivetrain.

The belt drive is a product called the Gates Carbon Drive - a polyurethane belt that replaces a traditional bicycle chain. Unlike a bicycle chain, the belt does not need to be oiled or otherwise maintained, which also means that it won't get the cyclist's clothing dirty. It is said to be longer lasting than a traditional chain. And it is silent. For these reasons, many praise the belt drive as a revolutionary innovation in cycling - particularly cycling for transportation.

On the downside, the belt drive requires a dedicated split-frame construction; it cannot just be retrofitted on any old bike. This is because the belt itself, unlike a traditional bicycle chain, cannot be split apart. In the picture above you can see that the seatstay of the Seven frame disconnects from the dropouts to make the belt installation possible (and that is a Surly Tuggnut chain tensioner they are using, in case you are wondering).

The belt's unique groove structure also requires it to be used with belt drive-specific front and rear pulleys instead of traditional chainrings and rear cogs. It is, however, compatible with standard cranks and hubs. The drive can be used with single speed and internally geared hubs, but not with derailleur drivetrains. As I understand it, it can be used with fixed gear and coaster brake bikes, as long as hand-activated brakes are present.

I rode the belt drive Cafe Racer for 5 miles or so along the Minuteman Trail in Lexington and Bedford MA. Compared to a traditional chain, the belt felt smoother and "softer." It was a neat sensation, distinctly different from cycling with a normal drivetrain. On first impression, I would say that it felt nicer. Although some describe the belt as silent, I would not say that exactly. It was definitely quieter than even the quietest traditional chain. But it made a gentle "swooshing" sound that I could hear whenever my surroundings grew silent. Additionally, I am pretty sure that I could feel something happen in the drivetrain at the end of every crank rotation. It was the subtlest of sensations, but definitely there. It was almost as if the belt had a seam in it, and I could feel when that seam went over one of the pulleys.

To be clear, neither the "seam" nor "swooshing" were something I would have noticed, had I not been intentionally paying very close attention and trying to take in every single aspect of the belt drive experience. They were more like ghostly traces than full-fledged sensations.

Prior to trying the belt drive myself, I'd read and heard a number of impressions from others. Alan from ecovelo is probably the "king" of belt drive test rides; he has tried at least half a dozen different bikes with this system and loves it. On one of his personal bikes, the belt drive has worked reliably for him for some time. Others (including commentators on ecovelo posts and persons I've spoken to locally) have reported a number of issues, such as squeaking noises, the belt slipping, and the system performing sub-optimally in winter conditions. I think that in order to get the big picture of how the belt drive performs, we need to wait until more cyclists use it for considerable periods of time, in different climates and weather conditions, and on a variety of bikes.

Next month I will be receiving another bicycle for a long term test ride that also happens to have a belt drive. No doubt I will have more to say after a few weeks of real-world experience with the system; maybe it will even start snowing by then. In the meantime, I am glad to have tried it on a different bicycle first - having done so will allow me to separate the feel of the belt itself from the feel of the specific bike. As far as first impressions go, mine are positive and I would love to see a classic city bicycle fitted with the Gates Carbon Drive... speaking of which, why do we never see that? The belt drive seems best suited for everyday commuting, yet most bicycles I see fitted with it are "weird" and "techy," if you'll pardon that biased terminology. An elegant belt drive city bicycle would be a delight to try.

56 comments:

Nice post. I feel sceptical towards belt drives for one reason - they are an expensive solution to a minor problem, and chains are doing a great job anyways. I kinda doubt that it will still be clean after a couple of weeks of riding and it will get your clothes dirty - maybe slightly less than a normal chain but still - chaincase solves that problem quite easily and you can retrofit it to any bike, unlike the belt drive. Add to that the requirement of having a perfect chainline and it becomes a very interesting, but expensive and slightly impractical thing.

This is going to sound really strange, but I think an older DL-1 would be a easy bike to fit with one of these. The fact that the seat-stays bolt into the seat tube should allow you to slip the thing on (unless I'm not thinking about that quite right- don't have the bike in front of me to look at it. Wrestling it into the chain guard might be "interesting" but should be do-able. Of course, the chain guard should be superfluous with the no-grease belt, although you could still get your clothes caught in the teeth.The main problem would be getting a belt drive crankset to play nice with either the Raleigh BB cups or the chaincase crank clearances.Hmmm. An intriguing idea, but not probably one I'm willing to follow up on. The upside (other than cool factor) isn't enough to deal with the crankset troubles.It would definitely be an "elegant city bike" to try it on though!Maybe it would be appealing to someone trying to convert a DL frame into something a little edgier (fixed gear roadster anyone?)

My wife and I have owned commuter/urban bikes with Gates belt drives for the past year. Just to add a couple of points to your review....

My experience has been that Gates belts smooth up a bit and become almost absolutely silent after about 50 miles of use. They're a bit noisier when completely new.

Neither of our belt drive bikes have the sensation of a seam in the belt while pedaling. I'm wondering if the sensation you're feeling might have something to do with the front belt pulley being slightly off in terms of roundness.

On fixed gear bikes, the belt needs to be installed somewhat tighter than it does on bikes with internal gear hubs, and that has led to a few issues which are resolved with the Gates Center Track belt--a newer design. The original Gates belt appears to work perfectly on bikes with IGHs. I haven't tried either in heavy snow.

Rohloff uses a small "snubber" pulley beneath the rear belt pulley which eliminates any belt skipping that may be related to the belt being a tad too loose. This seems to be a good idea.

All in all, our experience has been that the Gates belt drive lives up to the hype--it's quiet, reliable, clean, zero maintenance, and pedal response is better than it is with a chain. We find it a breakthrough level component that significantly improves the urban bicycling experience.

I've used bikes with chain cases for a number of years, and like others who have used them, including Alan at Ecovelo, have found chain cases much worse in practice than in theory.

They are bulky, usually low quality brittle plastic (even on high-end bikes) with small tabs connector tabs that break off easily.

Even when the chain is properly adjusted, it often rattles loudly when impacting the chain case over small bumps.

A number of chain case designs must be completely removed even to oil the chain--others have a rear port that can be removed.

Not to mention, that they add a lot of complexity and weight to the bike.

The Gates belt, on the other hand, simplifies the drivetrain. An urban bike with a belt drive, even one with an IGH, feels minimalistic, sort of like a fixed gear bike. The drivetrain is easy to access (although no longer really necessary), and the belt gets no more dirty than does, say, the frame.

In having used both chain cases and belt drives for quite some time, I don't regard the two as alternative solutions to the same problem. For me, the belt is preferable in every way.

Regarding the chain case vs the Gates belt - how does the belt drive compare in terms getting trouser / jean's pants legs caught in them? I understand that you shouldn't get grease stains on your pants anymore but are your trousers still prone to getting "eaten" by the belt drive the way a hungry, unprotected chain will do?

" I think an older DL-1 would be a easy bike to fit with one of these. The fact that the seat-stays bolt into the seat tube should allow you to slip the thing on... The main problem would be getting a belt drive crankset to play nice with either the Raleigh BB cups or the chaincase crank clearances..."

I was thinking the same thing. Unless I am misunderstanding how the belt installation works, any frame with a bolted rear triangle should be suitable. This is one of those projects I'd love to try but lack the budget for. Imagine, a vintage belt drive loop frame...

I haven't ridden one yet. I have been skeptical of them, however, based on the following criticisms/reports:

1. What problem do they solve that a completely encased chain does not solve more cheaply and flexibly, while offering true plain-clothes friendliness? Belt drives still present a pinch hazard to trouser cuffs. Want to encase the belt? [ok, i think i know the answer: it's a few grams lighter, and lack of a case makes it quicker to remove a rear wheel when the tire or tube must be replaced instead of repaired in place. am i missing something?]

2. To keep the belt from slipping off laterally or skipping under high load, the chainstay must be exceptionally stiff (i.e., heavier and/or larger in diameter). This has ride quality (and weight) consequences and can make it hard to achieve correct chainline (beltline?) with normal pulley sizes and comfortably fat tires. Frames that are under-engineered in this respect (a lot of early belt drive bikes) must compensate by setting the belt tension very high, which is hell on bearings in hub and bottom bracket, and makes the belt bind inefficiently. [the newish "center track" system seems to be a good address to the lateral slippage problem, but again at the expense of reliance on single-source, costly components available in a limited range of key specifications like length.]

3. I guess there is no need of a third when the first two are so verbose.

I tend to see belt drive as a way to "sex up" IGHs for markets that respond to novelty per se, hence the Carbon word (you called it polyurethane!), where chaincases just seem too quaint or fussy. Same thing with shaft drives: complex proprietary solution to a problem already solved by chaincases. Now, I admit that chain cases have their drawbacks too, but it seems to me a less formidable engineering challenge to improve chaincases than to invent away the venerable chain itself.

GR Jim - But think about it, wouldn't it be worth it marketing this system to the type of person who (1) doesn't want to get her nice cream trousers/stockings dirty, and (2) doesn't do her own maintenance? If I were on their marketing team, I'd insist the build up a classic step-through city bike model; would sell like hotcakes.

The Seven Cafe Racer rode so well it made me want to cry. Thankfully, its looks are outside the boundaries of my aesthetic open mindedness.

I know, it'd be theoretically perfect for someone who is so averse to maintenance. Kind of like an auto transmission in a dead quiet car for people who don't like to drive.

But my second comment points out "maintenance" is relative. Brushing teeth? Well, if I hafta...

It's a Seven so it's going to ride really well. It's well-known they are gunning for the title of World's Most Expensive Hybrid. Somebody forgot to cut down that head tube and went crazy with the protractor.

I purchased a belt drive Trek Soho in 2010. It was smooth, but never quiet. The combination of a roller brake equipped Nexus hub and belt made rear wheel changes tedious. Getting the belt re-aligned and properly tensioned was difficult. Lastly, the rear cog egged out its three lobes where they drive the hub after less than 500 miles. In conclusion, I'm not a fan and will stick with tried and true chain drives from now on. My '85 Schwinn Traveler is still on it's original drivetrain.

Sorry, I need to amend my muddled thinking: these are too new to be considered a perfect solution. Fine if folks want to be Beta testers, but it would take at least a few more iterations for me to even consider them. Not a fan of proprietary tech.

I think belt drive will be less prone to catching trousers than a regular chain because the chainring has a little grove on the outside. It's still possible, sure, but a minimalist top chain guard should reduce that even further. I think it has a lot of potential for city bikes.

Bicycle engineering is a field where there is a constant need to reinvent the wheel. Bicycle chain drives feel rough because they inherently are. A 12- tooth sprocket approximates a dodecagon more than it approximates a circle. Moving a chain over a polygon is going to be a bit rough. Chain drives used outside the world of bicycles rarely use less than 16 teeth and more is better.

The one serious attempt I am aware of to address the problem was the Chainette, with 9mm pitch, produced by Coventry Chain Company from 1909 to 1939. Instead of simply shrinking all dimensions as did the better known DuraAce 10, Coventry used sprockets with many more teeth. The drive was smooth, and was adopted by many racers, notably including Opperman.

Modern metallurgy would handily allow shorter pitch than was feasible in 1909. A more compact drive would have more clearance and be easier to enclose.The lure of reinventing the wheel is strong. The grip of 1/2" chain is strong. (Except that current chain is 12.7mm)

Kinda OT, but Velouria, did you ever find a modern cotterless crank set that would play nice with a chaincase? I know you posted a question to the Vintage Forum board, but didn't really see an answer.

Even the ones that don't have a dramatic "spider" seem like they might have too wide a connection to the ring to allow it to fit through a chaincase pieplate.I suspect that a lot of the ones on BSO's would actually work, but they're a) not widely available on the secondary market and b) probably crappy.

I wish there was someone who was the Raleigh equivalent of VO for French bikes- someone who makes repro, or at least old bike compatible modern parts.

I wonder if 100 years from now,our great great grand children will all be riding around on belt drives.

There isnt much I could say that hasn't been hinted at,if not said already,other than MHO,so I'll give that.

Belt drive may one day be a viable alternative to chain drive for city bikes like you mentioned (the ability to design and manufacture belt drive frames for all LBS-quality frame price ranges would be paramount-elsewise those who chose,or have to ride more budget oriented bikes will most likely see belt drive as a "fad for those with more money than sense"-and given that Raliegh itself offers their XXIX SS mountain bike for a reasonable,if not budget price,proves that it can be done-but we are't there yet). I'm very skeptical for cyclocrossers and mountain bikes,at least as a "better alternative" to chain drive. First hand experience of my own,as well as several friends and e-friends with the XXIX (and other) are the foundation of this skeptism. But that's a dirty subject,isn't it (trail riding)? LOL! The subject at hand is urban and city bikes.

If there were a quality budget priced urban or city bike with bet drive available,it would go a LONG way into getting it into more rider's quivers,and thereby become more mainstream,and there would be more real-world experience with the system,rather than those of select individuals who "have had one for a while now and love it",when they could however unintentionally be biased (they did after-all make a considerable investment in the thing...).

The thing is,the chain drive has been around for...how long? And is still as efficient today as it was the day it was made a viable drivetrain for bicycles,it will take much time,many thousands of miles,and many people of all walks of life and genre's of riding before belt drive could be considered "the other drivetrain" that's both relable and dependable (not to mention affordable to the masses of riders eveywhere).

Looking into the automotive world,however,I see how often,or,rather,how rarely as it were,I must change a belt on my car,how many thousands of miles...the theory is sound,IMHO. However,at least when it comes to mountain biking,I'll keep my chain thank you.

Since I have a Gates Center Track belt drive on my Shamrock Cycles commuter (http://www.flickr.com/photos/weichbrodt/sets/72157627733827597/), I can share a couple of thoughts to these comments in regards to commuting and belt drives after 6 weeks/350miles/lots of rain/90F-30F/crappy urban roads.

However, my Shamrock is almost certainly what Velouria would call a 'weird, techy' bike, so fair warning.

> squeaking noises, the belt slipping, and the system performing sub-optimally in winter conditions

squeaking and slipping mean the belt isn't happy. The belt gets unhappy when the tension is wrong, or it's not tracking straight. There's an iPhone app for tension checking. For tracking straight, well, that's tough to figure. My crank bolts loosened quickly after starting to ride, and the wobble on the front pulley cause the chain to creak. As for winter, well, it's been below freezing and perfectly happy. Belts are supposed to have consistent performance in all temperatures and weather.

>I kinda doubt that it will still be clean after a couple of weeks of riding and it will get your clothes dirty

Still clean. Dirt doesn't like to stay on the belt. Seems kinda an oleophobic surface.

>a very interesting, but expensive and slightly impractical thing

Interesting and expensive, yeah, I'll give you two out of three.

>it's quiet, reliable, clean, zero maintenance, and pedal response is better than it is with a chain

YES!

>Yep, clean urban environments might be where these excel. Not gonna hit the trails with that, no sir.

Um, might want to tell that to these guys: http://ridewithgarrett.wordpress.com/2011/10/17/podium-sweep

> any frame with a bolted rear triangle should be suitable

Yep.

> Belt drives still present a pinch hazard to trouser cuffs.

Nope. The centertrack pulley and belt treat a cuff like any other debris--when the tooth with debris hits the pulley, the grooves slide the debris off the tooth. My pants are happier than with a chain (oh, the many casualties to grease stains, even with a chainguard!)

> at the expense of reliance on single-source, costly components available in a limited range of key specifications like length

Yep. But you can design around the limitations. Would have liked to have a 116-tooth belt, but oh well. Cost gets amortized over the life of the components, which should be longer than chains.

> I'd insist the build up a classic step-through city bike model; would sell like hotcakes

You'd be the person to convince gates to change up their black/blue color scheme ^_^ But yeah, a nicely-done stepthrough would be sweet.

> an auto transmission in a dead quiet car for people who don't like to drive.

My other car is a 6-speed manual diesel.

> it would take at least a few more iterations for me to even consider them

MDI:In my experience, pant legs don't catch on the belt/front pulley because of the design feature you mentioned. I was surprised to discover that a top chain guard doesn't appear to be needed--nor even a pant leg clip.

Cycler:In my experience, to use a chain case it works best to use a crank specifically designed for it. It's fairly easy to buy a Gazelle crank designed for a chain case. www.cycleheaven.co.uk has them. Unlike most cranks, the left and right crank arms are sold individually.

The closest you have is Yellow Jersey in Madison. Andy originally imported the Eastman roadsters just so he could have the spares for you. No Eastmans left, lotsa spares. He also supports non-Raleigh rod brakes and old roadster stuff past imagination. Take any idea you've got to him, he's thought it through already if he hasn't prototyped it.

Hmm...the fact that Alan (god forbid if there is one speck of dirt in his bike photos) of ecovelo likes it should give you pause: you'd spend more of your time babying and adjusting and cursing this drive than actually using it. Didn't you read bikesnobNYC's experience with it?

Anon 4:39 - I read both Alan's and BikeSnob's reviews and suspect that the average experience lies somewhere in between. On the one hand, Alan probably does spend more time on bike maintenance than the average cyclist. On the other hand, BikeSnob's negative experience seemed to be based more on the specific bike he tried than on the belt drive itself (I was offered this same bike for review and declined, precisely because some of the problems he made fun of were obvious from the pictures alone). Keep in mind also that Alan has tried multiple belt drive bikes, whereas BikeSnob has tried just the one.

"did you ever find a modern cotterless crank set that would play nice with a chaincase"

The problem I had was specific to the Bella Ciao bike (when it was still just my personal bike and not a design project for the manufacturer). Or rathe, not a problem per se, but just that I did not like the look of their crankset (which fit just fine into the chaincase). The problem with using any other crankset, is that the chainrings they come with are not small enough to fit into the metal case. In theory this can be remedied by getting a custom made chainring, but I had been hoping for a cheaper solution. In the end I just learned to live with the Bella Ciao crankset. There is nothing functionally wrong with it; I just prefer more slender and "classic" looking cranks.

Been toying with the idea of putting a belt drive on my Dahon Curve foldingbike for light and dirtless drivetrain. Chainstay and seatstay is one oversized curved construction. Belt should be perfect for foldingbikes, light and no grease.badmother

Hebie (www.hebie.de) makes full chain cases that will work with modern cranks. They are limited to certain chainring and cog sizes as well as what length chainstays they will fit. They also are somewhat modern and technical looking compared to a classic chain case.

So if trouser cuffs don't get caught, how about a skirt hem? It rains a lot here, and I prefer a long rainskirt to rainpants. Consequently, the chaincase always wins on rainy days. Seems like a belt would just eat the flapping thing.

DC, Noel linked to some impressive pictures but I look at them and go, "yeah, but what are the other 70 dudes running?" Once you get to the point where you need both a smart phone and app to align the thing...well, you get my point. Stuff fails at an exponential rate in racing compared to normal riding. You can't win if you don't get to the end; belt drives haven't been proven enough to mitigate dnfs.

As for Hardly Ableson, guys around here tune and dress their bikes for "macho performance" and they go pretty quick for an agricultural engine, and they've had a long history of successful flat tracking, but those bikes and the ones you get at Burly Man HQ aren't remotely similar.

I fail to see why all the skepticism. From the first time I heard about Gates Carbon Drives over three years ago, I thought it was the perfect application for urban bikes. A year ago I retrofitted my favorite all-weather commuting bike, a Surly Cross Check, with a Gates Belt Drive. This year I upgraded to the CenterTrack (a really great 2.0) and ever since my other bikes, bikes that I love to ride, have been collecting dust.

The belt drive is buttery smooth, more responsive than a chain, quieter than a fixed gear, nearly maintenance free, and a pleasure to ride. A chain drive now feels gritty, even a clean one. And I can feel the chain stretch, the belt doesn't stretch at all. The belt should out last at least three chains. Over the long run the belt drive may even be cheaper.

Doug, when you're on that long ride and the belt breaks (as it has for me) all you can do is walk! For all the bad things that a chain might be, the fact that you can fix it on the side of the road out shines any of the good points that a belts might seem to have. I'd rather finish a ride with greasy hands and my butt in the saddle than walking my bike along the side of the road waiting for a ride. I have since converted my touring tandem to a chain drive. I'll never go back.

I bet a smart builder (Soulcraft comes to mind could come up with a retrofit kit that lets you split a rear stay. Something that bolts on like the Seven or screws together like a mini S&S coupler. Wouldn't be cheap, and someone would need to braze it on, but would let you retrofit onto the bike of your choice. Heck, maybe Seven should market that rear drop out to builders for just that.

There are many options for retrofittng. S&S makes couplers for many sizes of tubes including 3/4", the size of many seatstays. I used a Paragon Machine Works Tube Splitter. Paragon also make dropouts that split. I had my favorite framebuilder do the work. It cost less than the average American spends in gasoline for a month of driving.

Having said all that, it isn't even necessary because there are as many as 60 models of belt drive bikes on the market today. And more becoming available each year.

This is not really on topic to this or any other particular article, but I've just begun to read your blog recently, and although I think the blog is wonderful, this one thing has been driving me crazy. Why do you put brand names in italics? That's not correct according to any standard stylistic rules of English, and I wouldn't really care, but when I'm reading, it always makes me think there's some kind of strange emphatic tone being assigned to that particular word, so it's distracting. Just curious whether you do this for a particular reason or whether someone incorrectly told you it was a writing norm. Love the blog! =)

I've been intrigued for a while with Gates' belt drive and this is where this blog shines. It attracts a lot of different people who have, one way or another, actually experienced the thing. So much better than a forum in that regard. Love it... and the blog off course. ;)

I am riding one Fixie inc for several month now all in fixed gear only.Now to the issues;swooshing sound comes from lousy front sprocket that has 1.5 or 2.0mm runoff so you have fiddle with the wheel position,tension adjustment is not a big issue don't need a $60.00 tool for that, otherwise it is much better than I expected,now that I read all these comments maybe I shouldn't brake by back pedaling however if Harley's 1200cc and 200lb of torque doesn't bust the belt I am sure not be able to stretch it despite some totally moronic comments about stretch and longevity of the Gates belt ,it needs some more work since it is only 3 or 4 years in use and rushed to the market good old American way ; test it on the paying customer.

Greetings, those look like cafe-style racer handlebars. Would you mind sharing any/all details of that particular handlebar? I would like to find one in a different finish. Thanks for your time and effort!

I really think the belt drive thing is more of a novelty than anything. They are just trying to reinvent the wheel (chain). I have to admit I'd like to try one, but they gotta bring the price down if they want it to catch on.

Yeah, cool and all that and the belts last 4 to 5 times that of a chain. 80 km’s on a new tandem and we broken a belt!!! Can’t do much with a broken belt on the side of a road but walk. The following weekend, we broke a chain on the other tandem, fixed in 10 minutes and were riding again. The new tandem was over a week before we could get a belt. So, a belt might be like a leash but at least it won’t let you down if it breaks! Ultimately, you have to decide if those 118 grams of weight savings are worth anything when the belt is broken on the side of the road in the middle of a long ride!!! By the way, I an converting the new tandem to chain drive! Sure a carbon belt might weigh less, but I was told not to kink it or it might compromise its strength and longevity, maybe they should have made it out of kevlar, it is much more durable and flexible and certainly less likely to break, but then again, you can't fix it - EVER!

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